John Isner talking with media after pulling out of the Winston-Salem Open due to injury, August 19, 2013. Courtesy WFMY News 2.

WINSTON-SALEM, N.C. -- The first and third-seeded players at the Winston-Salem Open, Tomas Berdych and John Isner (respectively), have withdrawn from the tournament, citing injuries.

Isner, from Greensboro, withdrew because of an ongoing hip injury that was aggravated in Cincinnati last week.

Berdych said a shoulder injury caused him to drop out of the tournament. He reached the semifinals at the Western & Southern Open in Cincinnati last week.

Isner was a runner-up against former world No. 1 star Rafael Nadal at the ATP Masters 1000 event in Cincinnati on Sunday. The surging American recently titled in Atlanta and was also a hardcourt runner-up in Washington, D.C., earlier this month.